wireshark: Stack-based buffer over-read from tvbuff buffer when reading snoop capture files

The snoopread function in wiretap/snoop.c in Wireshark 1.2.x before 1.2.17 and 1.4.x before 1.4.7 does not properly handle certain virtualizable buffers, which allows remote attackers to cause a denial of service application crash via a large length value in a snoop file that triggers a stack-bas...